How do you do two-step equations?

A:

Quick Answer

To solve two-step equations, simplify both sides of the equation by removing extra terms, then remove coefficients. It's also possible that a variable will exist on both sides of the equation. In this case, you need to isolate the variable.

For example, take the equation 3x + 9 = 5x -15. To avoid negatives, add 15 to both sides, leaving you with 3x + 24 = 5x. No matter which term you choose to cancel out, the equation ends up with the same result, so it's a matter of personal preference.

Get the variable on one side of the equation

Subtract 3x from both sides of the equation, leaving you with 24 = 2x. You could have also subtracted 5x, but this adds an extra step to the equation because the 24 would have to be moved again.

Divide by the coefficient of x to simplify the variable

In this case, the coefficient of x is 2, so also divide 24 by 2, yielding the result as 12. Substitute it into the original equation, and check to solve. 3(12) + 9 = 5(12) - 15 simplifies to 45 = 60 - 15, which equals 45 and thus satisfies the equation.